'From Squeak3.9 of 7 November 2006 [latest update: #7067] on 16 April 2007 at 3:43:09 pm'!List subclass: #Relation	instanceVariableNames: ''	classVariableNames: ''	poolDictionaries: ''	category: 'Prolog'!!Relation methodsFor: 'adding' stamp: 'mt 6/28/1999 12:00'!add: anObject    (content isNil and: [link isNil])        ifTrue: [            content := anObject.            link := EmptyList new]        ifFalse: [super add: anObject].    ^anObject! !!Relation methodsFor: 'printing' stamp: 'mt 6/28/1999 12:00'!printOn: aStream    content printOn: aStream.    aStream nextPut: $(.    (link isKindOf: List)        ifTrue: [link printOne: aStream]        ifFalse: [link printOn: aStream].    aStream nextPut: $)! !"-- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- "!Relation class	instanceVariableNames: ''!!Relation class methodsFor: 'instance creation' stamp: 'mt 6/28/1999 12:00'!new    ^super basicNew! !